Grinding machine



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GRINDING MACHINE 'Filed Aug. 4. 1951 15 Sheets-Sheet 15 F E E D OF UPPERSLIDE 4496 TACK/N6 FEED T?!Untar 'HERBERT A. S/LVEN istanze/V UnitedStates Patent Office 2,710,494 Patented June 14, 1955 GRINDING MACHINEHerbert A. Silven, Worcester, Mass., assignor to Norton (lomlasny,Worcester, Mass., a corporation of Massac use Application August 4,1951, Serial No. 240,378

22 Claims. (Cl. 51-50) The invention relates to grinding machines, andmore particularly to a universal-type grinding machine.

One object of the invention is to provide a simple and thoroughlypractical grinding machine for grinding or regrinding a wide variety ofworkpieces. Another object is to provide a grinding machine wherebyworkpieces may be ground either on centers or may be ground whilemounted on a face plate. Another object is to provide a double swivelwheel head whereby a wide variety of angular surfaces on a workpiece maybe ground.

A further object of the invention is to provide hydraulically actuatedgrinding Vwheel carriage and grinding wheel slides with hydraulicallyactuated nut and screw mechanism for traversing the carriage to positionthe grinding wheel relative to the work to be ground, and also to feedthe grinding wheel transversely to grind the workpiece to the desiredand predetermined extent. Another object is to provide a hydraulicallyactuated electrically controlled mechanism for remotely controlling thepositioning movement of the grinding wheel carriage. Another object isto provide a hydraulically actuated electrically controlled mechanismindependently to feed both of the cross slides by a remote controlthereof. Another object is to provide independent manually operableremote control mechanisms for the grinding wheel carriage traversingmechanism and for both an upper and lower cross slide feeding mechanismsin which there is no mechanical connection between the control mechanismand the actuating mechanism therefor whereby the carriage and slides maybe precisely adjusted during a grinding operation. A further object isto provide a tacking-type feed mechanism whereby an angularly arrangedwheel spindle may be manually adjusted axially to impart a precisetransverse feeding movement of the grinding wheel. Other objects will bein -part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction,arrangements of parts, as will be exemplified in the structure to behereinafter described, and the scope f the application of which will beindicated in the following claims.

One embodiment of the invention has been illustrated in the drawings, inwhich:

Fig. 1 is a front elevation of the improved grinding machine;

Fig. 2 is a fragmentary plan View of the grinding machine with the uppercontrol panels .and mounting therefor removed; f

Fig. 3 is a combined electric and hydraulic diagram of the actuatingmechanismsof the machine and the controls therefor; f

Fig. 4 is an hydraulic diagram, on an enlarged scale, of the controlsand actuating mechanism for the longitudinally movable carriage; j l lFig. 5 is a combined electrical and hydraulic diagram, on anenlargedscale, of the controls and actuating mechanism for the'upperslide;`

, Fig. 6 is a combinedlelectrical 'and hydraulic diagram on an enlargedscale, of the controls and actuating mechanism for the lower slide;

Fig. 7 is a vertical sectional view, on an enlarged scale, through theheadstock;

Fig. 8 is a vertical cross-sectional view, on an enlarged scale, takenapproximately on the line 8 8 of Fig. 1, through the grinding machine;

Fig. 9 is a fragmentary detail View, on an enlarged scale, of thegrinding wheel carriage traversing and positioning mechanism; y

Fig. 10 is a fragmentary front elevation, partly in section on anenlarged scale, of the reversing control mechanism for thelongitudinally movable carriage;

Fig. l1 is a plan View of the mechanism shown in Fig. 10;

Fig. 12 is a fragmentary cross-sectional view, taken approximately onthe line 12--12 of Fig. 1l;

Fig. 13 is a fragmentary vertical sectional view, on an enlarged scale,through the nut and screw feed mechanism for the upper and lower slides;

Fig. 14 is a fragmentary detail view, on an enlarged scale, of the tineadjusting mechanism for controlling thev swivelling movement of theupper slide and its supporting slide;

Fig. 15 is a vertical sectional view, taken approximately 0n the line15-15 of Fig. 14;

Fig. 16 is a fragmentary front elevation, on an enlarged scale, of thelower control station on the front of the machine, having the coverremoved so as to show the control valves;

Fig. 17 is a fragmentary vertical sectional view, taken approximately onthe line 17-17 of Fig. 16, through the manual control for the upperslide;

Fig. 18 is a fragmentary sectional view, taken approximately on the line18-18 of Fig. 17;

Fig. 19 s a fragmentary front elevation, on an enlarged scale, of theupper control station on the longitudinally movable carriage, having thecasing removed to show the control valves;

Fig. 20 is a plan view of the upper control station as shown in Fig. 19;

Fig. 2l is a vertical sectional view, on an enlarged scale, through thegrinding Wheel head, showing the wheel spindle positioning mechanism;

Fig. 22 is a vertical sectional view, taken approximately on the line22-22 of Fig. 21, through the wheel spindle actuating mechanism;

Fig. 23 is a front elevation of an internal grinding attachmentremovably mounted on the front of the wheel head;

Fig. 24 is a left-hand end elevation of the internal grinding attachmentas shown in Fig. 23;

Fig. 25 is a diagrammatic view showing the grinding machine set-up toemploy a tacking feed;

Fig. 26 is a diagrammatic view showing the grinding machine set-up for ashoulder or side face grinding operation;

Fig. 27 is a diagrammatic View showing the grinding machine set-up for asurface grinding operation; and

Fig. 28 is a diagrammatic view showing the grinding machine set-up foran internal grinding operation.

The improved grinding machine has been illustrated in the drawingscomprising a base 10 which supports a swivel table 11. The swivel table11 is arranged to pivot on a stud 12 which is tixedly supported on thebase 10. A pair of guides and clamping blocks 13 and 14 are provided onthe base 10 for engaging and clamping opposite ends of the swivel table11 in adjusted position to the base 10.

The swivel table 11 serves as a support for a headstock 15 and afootstock 16 is rotatably supporting a workpiece during a grindingoperation (Fig. 7).

The headstock is provided with a rotatable headstock spindle 17 which isjournalled in anti-friction bearings 18 and 19 within the headstock 15'.The headstock spindle 17 is provided with a headstock center 20 forrotatably supporting the left-hand end of a workpiece. The footstock 16is similarly provided with a footstock center 21 for rotatablysupporting the righthand end of a workpiece during a grinding operation.

A suitable driving mechanism is provided for the headstock spindlecomprising an electric motor 25 mounted on top of the headstock 15. Themotor 25 is provided with an armature shaft 26 having a multipleV-groove pulley 27 which is connected by multiple V-belts 28 with apulley 29 mounted on a shaft 30. The shaft 30 also supports a multipleV-groove pulley 31 which is connected by multiple V-belts 32 with amultiple V-groove pulley 33 mounted on a rotatable shaft 34. The shaft34 is connected by means of a sprocket and link chain (not shown) with asprocket 37 which is journalled on anti-friction bearings 38 on thewheel spindle 17. The spindle is arranged so that it may be operated asa live spindle headstock or a dead center headstock. The sprocket 37 isconnected by a stud 35 with a face plate or driving plate 39. In theposition as illustrated rotary motion transmitted to the sprocket 37will be imparted to rotate the work driving plate 39 while the workcenter remains stationary, The driving plate 39 is provided with adriving pin 40 which is arranged to engage either a portion of theworkpiece to be ground or a work driving dog mounted thereon.

A suitable mechanism is provided for holding the headstock spindle 17stationary when it is desired to operate the headstock for dead centergrinding. This mechanism may comprise a gear 41 which is keyed on thespindle 17 (Fig. 7). A slidably mounted locking pin 42 is arranged to bemoved into engagement with the teeth of the gear 41 to lock the spindle17 or may be withdrawn from engagement therewith if a live spindlegrinding operation is to be performed. The locking pin 42 is slidablymounted within an aperture 43 formed within the headstock 15. Thelocking pin 42 is connected by a screw 44 with a block 45 having acylindrical aperture 46 therein which engages an eccentric portion 47 ofa rotatable shaft 48. The shaft 48 is journalled in bearings 49 and S0which are mounted in the headstock 15. An actuating knob 51 is mountedon the right-hand end of the shaft 48 to facilitate actuation of thelocking pin 42.

If it is desired to operate the headstock 15 as a live spindleheadstock, the stud 35 may be moved toward the left (Fig. 7) intoengagement with a hole in a plate 36 which is keyed to the headstockspindle 17. The actuating lznob .5l is then rotated to withdraw thelocking pin 42 thereby unlocking the spindle 17. ln this position of theparts, it will be readily apparent that rotary motion transmitted to thesprocket 37 will be imparted through the stud 35 to rotate the workdriving plate 39 and also to rotate the plate 36 and the headstockspindle 17.

The headstock 1S is also provided with a relatively large face platewhich is mounted on the left-hand end of the headstock spindle 17 (Fig.7). It is desirable to provide a suitable swivel adjustment for theheadstock 15 so that the parts may be shifted to facilitate either acenter type grinding operation or a face plate type grinding operation.The headstock 15 is pivotally supported by a vertically arranged stud 56carried by a base plate 57 which is clamped onto the upper surface ofthe swivel table 11. A pair of clamping bolts 58 and 59 are mounted ondiametrically 0pposite sides of the pivot stud 56. The clamping bolts 58and 59 pass through clearance holes in the headstock 15 and their headsare slidably supported in a circular T-slot 60 formed in the base plate57j. It will be readily apparent from the foregoing disclosure that.

by loosening of the clamping bolts 58 and 59, the headstock 15 may beswivelled through 360 so as to present either the driving plate 39 andthe work center 20 into an operative position, or to position theheadstock 15 so that the face plate 55 is in the desired position for agrinding operation.

The grinding machine as illustrated, is a travelling wheel type machinein which the grinding wheel to be hereinafter described is supported bya longitudinally traversable grinding wheel carriage 65 which isarranged to slide longitudinally on a V-way 66 and a flatway 67 (Fig. 8)formed on the upper surface of the base 10. The grinding wheel carriage65 is provided with a suitable traversing mechanism comprising a nut 68depending from the underside of the carriage 65. The nut 68 meshes witha rotatable screw 69. The screw 69 is journalled in spaced bearings 70and 71 supported by the base 10. The rotatable screw 69 is provided witha gear 72 which meshes with a gear 73 mounted on a rotor shaft 74 of afluid motor 75. Fluid under pressure is admitted to and exhausted fromthe uid motor 75 through a pair of pipes 301 and 302 in a manner to behereinafter described.

The grinding wheel carriage 65 is provided with a transversely arrangedV-way and a atway 81 which serve as supports for a cross slide 82. Theupper portion of the cross slide 82 is circular in shape and supports aswivel plate 83. The swivel plate 83 is arranged to swivel about avertically arranged pivot stud 84. The swivel plate 83 is provided witha transversely arranged V-way 85 and a atway 86 which are arranged tosupport a transversely movable wheel slide 87. The upper portion of thewheel slide 87 is circular in shape and is arranged to support a wheelhead 88. The wheel head 8S is arrranged to swivel about a verticallyarranged pivot stud 89 carried by the wheel slide 87. The wheel head 88serves as a support for a rotatable wheel spindle 90 which is journalledin suitable bearings 420 and 421 (Fig. 21) mounted within the wheel head88. The wheel spindle 90 supports a pair of grinding wheels 91 and 92 atopposite ends thereof. The spindle 90 may be driven by any suitablemechanism such as for example a motor 93 mounted on the upper portion ofthe wheel head 88. The motor 93 is provided with a motor shaft 94carrying a multiple V-groovc pulley 95. The pulley 95 is connected bymultiple V-belts 96 with a multiple V-groove pulley 97 mounted on thewheel spindle 90. It will be readily apparent that actuation of themotor 93 will transmit a rotary motion to the grinding wheels 91 and 92.

A nut andscrew feeding mechanism is provided between the carriage 65 andthe lower cross slide 82 whereby a transverse movement of the wheel headtogether with the intermediate parts may be obtained. This mechanismcomprises a rotatable screw 100 Fig. 13) which is supported by a pair ofspaced anti-friction bearings 101 and 102 mounted in the base 10. Thescrew 100 meshes with a nut 103 which is tixedly mounted on the underside of the cross slide 82. The feed screw 100 carries a gear 104 whichmeshes with a gear 105. The gear 105 is mounted on a rotor shaft 106 ofa fluid motor 107. Fluid under pressure is conveyed to and from thefluid motor 107 through a pair of pipes 282 and 283 in a manner lto bchereinafter described.

A nut and screw feeding mechanism is provided between the swivel plate83 and the upper slide S7. A rotatable feed screw 110 is supported atone end in anti-friction bearings 111 in a slidable sleeve 112 which iskeyed within a cylindrical aperture 113. The other end of. the feedscrew 110 is slidably keyed within a rotatable sleeve 114. The sleeve114 is journalled in anti-friction bearings 115 and 116 which aresupported by the swivel plate 83. A reduced cylindrical portion 117 ofthe feed screw 110 is slidably keyed within an aperture 118 in thesleeve 114 to to facilitate an axial movement' of the feed'screw 110 forrapidly moving the Wheel slide 87 and the wheel head 88 into an.operative or inoperative position.

In order to impart a feeding movement to the upper slide 87, a bevelgear 124 is keyed on the right-hand end of the sleeve 114 (Figs. 3 and13). The bevel gear 124 meshes with a bevel gear 125 carried by a shaft126. The shaft 126 is connected by a pair of bevel gears 127 and 128with a rotor shaft 129 of a fluid motor 130. Fluid under pressure isadmitted to and exhausted from the motor 130 through a pair of pipes 131and 132 in a manner to be hereinafter described. It will be readilyapparent from the foregoing disclosure that a double swivel adjustmentis provided, namely, the wheel head 88 may be swivelled relative to theupper slide 87 and the swivel plate 83 may be swivelled relative to thelower slide 82 to facilitate grinding angular and shouldered or sidefaces on a workpiece being ground. In any position of the swivel plate83, the wheel head 88, the lower slide 82 may be fed transverselyrelative to the base and the upper slide 87 may be fed transverselyrelative to Vthe swivel plate 83. By a combination of feeding movements,any angular surface may be ground on a workpiece either mounted on thework centers and 21 or on the face plate 55.

A fluid pressure system is provided for supplying fluid under pressureto the various operating mechanisms of the machine. This system maycomprise a motor driven fluid pump 135 (Fig. 3) which draws fluidthrough a pipe 136 from a uid reservoir 137. The pump 136 forces fluidunder pressure through a pipe 138 to the various operating mechanisms ofthe machine. A pressure relief valve 139 is connected with the pipe line138 so that excess fluid under pressure may be bypassed through a pipe140 into the reservoir 137.

It is desirable to provide a rapid approaching movement for the upperslide 87 to facilitate rapidly moving the grinding wheels to and from anoperative position before and after a grinding operation. Ahydraulically operated mechanism is provided comprising a cylinder 145which is arranged in axial alignment with the feed screw 110. Thecylinder 145 contains a slidably mounted piston 146 which is connectedto one end of a piston rod 147. The other end of the piston rod 147 isiXedly connected to the slidably mounted sleeve 112 (Fig. 13) so thatmovement of the piston 146 will cause an axial movement of the feedscrew 110 rapidly to move the upper slide 87 to and from an operativeposition. A suitable control mechanism is provided for controlling theadmission to and exhaust of fluid from the cylinder 145. This controlmechanism may comprise a control valve 148 having a slidably mountedvalve member 149 which is arranged to be shifted by means of fluid underpressure admitted to and exhausted from chambers formed in the oppositeends of the valve 148 (Figs. 3 and 8). A pilot valve 150 is provided forcontrolling the shifting movement of the valve member 149. The pilotvalve 150 is normally-held in a right-hand end position by means of acompression spring 151. A solenoid S8 is provided for shifting the pilotvalve into a left-hand end position so as to admit fluid under pressureinto the left-hand end chamber to shift the valve member 149 toward theright so as to change the direction of fluid under pressure passingthrough a pair of pipes 152 and 153 which connect the valve 148 with thecylinder 145. A switch PB9 ora switch PB10 may be actuated to energize arelay switch CR11 to energize the solenoid S8 to initiate a rapidforward movement of the upper slide 87. A throttle valve 158 (Fig. 3) isprovided for controlling the return of fluid exhausting from the valve148 into the pipe 188 and the reservoir 137. -A switch PB11 or a switchPB12 may be actuated to breakv the circuit thereby deenergizing thesolenoid S8 to return the upper slide 87 to a rearward position.- Y

It is desirable to provide suitable meansfor slowing down the rapidapproaching movement before the piston 146 reachesthe end of its strokein either direction. This is preferably accomplished by provision of apair of throttle valves 154 and 155 which are arranged to control theadmission of uid into the cylinder after the main port has been closed.A pair of ball check valves 154a and 155a are provided to allow uidunder pressure to pass in one direction unrestricted by bypassing aroundthe throttle valves 154 and 155 respectively.

In a large universal type machine, such as disclosed, it is desirable toprovide adequate controls for the various mechanisms of the machine sothat the operation thereof may be readily controlled from the front ofthe machine base or from an operators control station 160 or 161 on thelongitudinally reciprocable carriage 65 (Fig. 2). A control unit 162 ismounted on the front of the machine base (Figs. l and 16). This controlunit is provided with a plurality of hand wheels consisting of a handwheel 163 for controlling the movement of the upper slide 87, a handwheel 164 for controlling the lower slide 82 and a hand wheel 165 forcontrolling the carriage 65. An electrical control panel 166 is mountedabove the control unit 162 (Figs. 1 and 16) whereby the various unitsmay be controlled from the front of the machine base.

A similar control unit 162a is mounted on a bridgetype frame 168 (Figs.l and 19) which is supported on the longitudinally movable carriage 65.The control unit 162a also is provided with a plurality of hand wheels,a hand wheel 1630: for controlling the upper slide 87, a hand wheel 164afor controlling the lower slide 82 and a hand wheel 165a for controllingthe movement of the carriage 65. An electrical control panel 166a ismounted on the upper portion of the control unit 162a to facilitatecontrolling the electrical units of the machine. An electric light bulb156 on the upper control unit 162a is connected in series between thesolenoid S3 and one side of the power lines which is illuminated whenthe solenoid S8 is energized visibly to indicate that the upper slide isin a forward position.

In order that the upper control unit 162a may be readily accessible andwithin easy reach of either the control station 160 or 161, the controlunit is preferably pivotally mounted on a pivot stud 167 (Fig. 20)supported on the bridge-type frame 168. The bridge-type frame 158 isprovided with an arcuate shaped plate 169 which serves as a slideway forthe control unit 162a. A clamping screw 170 (Figs. l and 19) passesthrough an elongated arcuate slot 171 (Fig. 20) formed in the plate 169and s screw threaded into a nut 172 carried by the unit 162a. It will bereadily apparent from the foregoing disclosure that by loosening of theclamping screw 170, the control unit162a together with the electricalcontrol panel 166e may be readily swivelled on the pivot stud 167 so asto bring the hand wheels 163:1, 164a and 165a together with the pushbuttons on the electrical control panel 166a within easy reach of thecontrol station 160 or 161.

The hand wheels 163, 163a, 164, 164a, 165 and 165a are each operativelyconnected to actuate independent control valves in a manner to behereinafter described. The mechanical connections between these handwheels and the respective control valves are identical on construction,consequently only one of these mechanisms has been illustrated indetail. As shown in Figs. 16, 17 and 18, the hand wheel 163 is keyed ona sleeve 174 which is in turn rotatably supported on a fixed shaft 175.A gear 176 is keyed on the sleeve 174 and meshes with a rack bar 177.The rack bar is connected by means of a rod 178 with a valve stem 179 ofa control valve 180. A compression spring 181 is provided normally tohold the valve stem 179 and the associated parts in a central position.A cam 182is keyed on the sleeve 174 and is arranged to actuate either inactuating arm 183 or an actuating arm 184 of a limit switch LS1 or alimit switch and the cross slide 82, respectively, are preferablyswashplate type rotary motors, such as, manufactured by SundstrandMachine Tool Co. of Rockford, illinois, and covered by U. S. patent toG. A. Wahlberg, No. 2,285,476 dated June 9, 1942.

In order to provide precise and positive control of the fluid motors 107and 130 for controlling transverse movements of the lower slide 82 andthe upper slide 87, rcspectively, balanced fluid under pressure isnormally supplied through valves 200-260 to both pipes 131-132 and282-283 leading to each of the uid motors 130 and 107 respectively tohold the motors stationary. When it is desired to impart a feedingmotion either to the lower slide 82 or the upper slide 87, the fluidpressure to one side or the other of the motor is opened to the exhaustthereby allowing the motor to transmit the desired feeding movement toeither the feed screw 100 or the feed screw 110.

Actuation of either the control wheel 164 or 16411 in acounter-clockwise direction serves to actuate limit switches LS3 or LS7respectively which are connected in parallel to energize S3 to shift thepilot valve 254 toward the right thereby shifting the valve member 261toward the left so that pressure from the pipe 138 passes through thepipe 282 to apply pressure to one side of the Huid motor while cuttingit off from the other side. At the same time movement of the controlwheels 164 and 164a in a counterclockwise direction serves to shift thevalve 240 or 240:1 respectively toward the right to allow exhaust offluid from the other side of the motor 107 through the pipe 283. Ifeither the control wheel 164 or 164a (Fig. 5) is turned only a slightdistance, iluid passes through a chamber in the valve 240 or 240a outthrough a port 245 or 2450 and through a throttle valve 247 and throughthe exhaust pipe 188 to cause the motor 107 to rotate at a slow speed tocause an inching feed movement of the lower slide 82 in one direction.If either the hand wheel 164 or 164g is moved to a greater extent in acounter-clockwise direction, the Valve 240-240a is shifted furthertoward the right so that uid exhausting through the pipe 132 passesunrestricted through the ports 256 or 256:1 directly to the exhaust pipe188 to cause a fast feeding movement of the slide 82 in the samedirection.

If either the control wheel 164 or 164a is rotated in a clockwisedirection, the limit switch L84 or L58 is actuated to energize solenoidS4 to shift the pilot valve 264 toward the left so that the valve member261 is shifted toward the right. Fluid from the pressure pipe 138 passesthrough the pipe 283 to the opposite side of the motor 107. At the sametime the valves 180-180.@ are moved toward the left to uncover the ports249-2490' or the ports 257-257a to obtain either a slow or a fastexhaust of fluid from the uid motor 107 through the pipe 283 to controlthe speed of the movement of the motor 107 in the reverse direction.

Actuation of either the control wheel 163 or 163a in a counter-clockwisedirection serves to actuate limit switches LS1` or LS5 respectivelywhich are connected in parallel to energize S1 to shift the pilot valve204 toward the right thereby shifting the valve member 201 toward theleft so that pressure from the pipe 138 passes through the pipe 131 toapply pressure to one side of the fluid motor 130 while cutting it oiffrom the other side. At the same time movement of the control wheels 163and 163a in a counter-clockwise direction serves to shift the valve 180or 18011 respectively toward the right to allow exhaust of fluid fromthe other side of the motor 130 through the pipe 131. If either thecontrol wheel 163 or 163:1 (Fig. 6) is turned only a slight distance,uid passes through a chamber in the valve 180 or 180a out through a port185 or 185a and through a throttle valve 187 and through the exhaustpipe 188 to cause the motor 130 to rotate at a slow speed to cause aninching feed movement of the upper slide 87 in one direction.

If either the hand wheel 163 or 163a is moved to a greater extent in acounter-clockwise direction, the valve -180:1 is shifted further towardthe right so that fluid exhausting through the pipe 132 passesunrestricted through the port 196 or 196:: directly to the exhaust pipeto cause a fast feeding movement of the slide 87 in the same direction.

If either the control wheel 163 or 163a is rotated in a clockwisedirection, the limit switch LSZ or LSG is actuated to energize solenoidS2 to shift the pilot valve 204 toward the left so that the valve member201 is shifted toward the right. Fluid from the pressure pipe 138 passesthrough the pipe 132 to the opposite side of the motor 130. At the sametime the valves 180-180:1 are moved toward the left to uncover the ports189-189a or the ports 197-197a to obtain either a slow or a fast exhaustof fluid from the uid motor 130 through the pipe 131 to control thespeed of the movement of the motor 130 in the reverse direction. Bycontrol of the throttle valve 187, the rate of rotation of the feedscrew 110 may be readily varied as desired. A similar port 189 isprovided so that when the hand wheel 163 is rotated in a clockwisedirection, the valve stem 179 will be shifted so as to open the port 189which allows uid to exhaust from the other side of the motor through thesame throttle valve 187 into the exhaust pipe 188 to control therotation of the feed screw 110 in the opposite direction.

A suitable mechanism is provided normally to limit the rotation of thehand wheel 163 in either direction so that only sufficient movement isimparted to the valve stem 179 to open either the port 18S or the port189 depending upon the direction of rotation of the hand wheel 163. Thismechanism may comprise a slidably mounted stop pin (Fig. 17) which issupported by the hand wheel 163. The right-hand end of the pin 190 rideswith an elongated arcuate slot 191 having a pair of stop surfaces 193and 194 formed in a plate 192 which is fxedly mounted relative to thevalve 180.

For a rapid transverse movement of the upper slide 87, it is desired tobypass uid around the throttle valve 187 so that a rapid movement of theupper slide 87 may be obtained when desired. A rock arm is pivotallysupported on the hand wheel 163. When it is desired to obtain a rapidmovement of the upper slide 87, the rock arm 195 may be rocked in aclockwise direction (Fig. 17) to withdraw the pin 190 from the slot 191so that an increased rotary motion of the hand wheel 163 is permitted.The increased rotary motion of the hand wheel 163 serves to cause anincreased motion of the valve stem 179 in either direction dependingupon the direction of rotation of the hand wheel 163 so as to openeither an exhaust port 196 or an exhaust port 197 which exhaust fluidfrom the motor 130 directly through the pipe 188 into the reservoir 137.

The hand wheel 163a is supported on a shaft 175i: carried by the uppercontrol unit 162:1. A cam 18251 is keyed to rotate with the hand wheel163g and is arranged to actuate the actuating arms 18311 and 184 of apair of limit switches LSS and LS6 respectively when the hand wheel isrotated in either direction. A gear 17651 is keyed to rotate with thehand wheel 163n aud meshes with a rack bar 177a. The rack bar 177a isconnected by a rod 17811 with a valve stem 179a of a control valve180er. A compression spring 181a serves normally to hold the valve stem179a in a central position. The valve 180g is identical in constructionwith the valve 180 and is provided with ports 185:1, 1.89m. 196g and1970 which are connected with the pipes 1851-1 and 188 respectively. Inthe normal operation of the hand wheel 163a that is for an inching feed,the hand wheel 163a is rotated either in a clockwise direction orcounter-clockwise direction to open either the port 189.11 or the port1,854 SQ that tuid may exhaust through the pipe 186a, through the commonthrottle valve 187 and out through the exhaust pipe 188., If itisdesired to cause a rapid movement of the upper wheel slide, therock arm19511 is rocked to withdraw the slide pin (not shown) to allow a furtherrotary motion of the hand wheel 163:1 so as to open either the ports196a or 19711 so that fluid exhausting from the system may bypass .thethrottle valve 187 and pass directly into the exhaust pipe 18S. The handwheels 163 and 163a as above described are connected in parallel so thatactuation of either hand wheel operates to control the stopping andstarting of the upper slide motor 130. The mechanisms above describedcontrolled by the hand wheels 163 and 163:1 serve to provide acontinuous slow or fast infeed of the upper slide in either direction.

It is desirable to provide a pick feed mechanism where? by the upperslide may be advanced in a forward or rearward direction by apredetermined increment each time the mechanism is actuated. Thismechanism is preferably arranged so that a pick or incremental feed maybe obtained either in a forward direction for an external grindingoperation or in a rearward direction for an internal grinding operationas desired. This mechanism may consist of a fluid actuated control valve200 having a slidably mounted valve member 201 which is normally held ina central position by a pair of compression springs 202 and 203 locatedin the opposite end chambers of the valve 200. A pilot valve 204 isprovided for controlling the shifting movement of the valve 200. Thepilot valve 204 is normally held in a central position as illustrated inFig. 5 by opposed compression springs.

A solenoid S1 and a soleneoid S2 are provided to shift the pilot valve204 in opposite directions to control the direction of flow of uid tothe fluid motor 130. When the solenoid S1 is energized, the valve 204 isshifted toward the right to pass fluid into the right-hand end chamberof the valve 200 to shift the valve member 201 toward the left so thatfluid under pressure from the pressure pipe 138 may pass through a valvechamber 205 and out through the pipe 131 so that when fluid is exhaustedfrom the other side of the motor a transverse feeding movement may beobtained in a forward direc.

pair of pushbutton switches PB7 on the upperrcontrolunit 162a and PBS onthe lower control unit 162. 'Ehepushbutton switches PB7 and yPB8 areconnected in parallel to start an electric timer- 221 to close acircuit. A selector switch SL2 is provided so that either a magneticswitch CR@ or amagnetic switchCRlO maybe actuated to energize thesolenoids S1-v and S2 respectively so as to cause either a feedingmovement in a forward or rearward direction depending upon the set-up ofthe machine. Ifthe selector switch is rotated in aclockwise direction,the magnetic switch CRS is connected so that when either the pushbuttonswitch PB7 or PBS are actuated the timer 221 will be started to energizethe switch CRS thereby energizing the solenoid VS1 to .shift the valvemember 201 to cause a forward feeding increment of the upper slide motor130.

Similarly if the selector switch is rotated in a counter clockwisedirection the magnetic switch CRll.)l is connected so that when thetimer 221 is set in motion `the magnetic switch CR10 is closed toenergize the solenoid S2 so as toshift the valve member 201 in adirectiontoward the right to pass fluid under pressure so as to cause arearward feeding increment of the motor 130.. The electric timer 221 isadjustable so that the duration of the pick or increment may be adjustedas desired.

After the timer has run for the set period-magneticl switch CRS o r themagnetic switch CR10`is deenergizedk thereby deenergizing either thesolenoid S1 or the solenoid S2 to allow the valve member 201 to returnto a central or neutral position.

In order to give a precise control of the pick or incremental feed, asuitable mechanism is provided for conz trolling the exhaust of fluidfrom the motor 130. This from the pipe 13S passes through a valvechamber in y which is actuated by the hand wheels 164 and 16411.

thevalve 209, through a pipe 220 into a left-hand end chamberV of thevalve 213 to maintain the valve 213 in its extreme right-hand endposition. When either the magnetic switch CRS or CR10 is energized,contactors therein serve to close a circuit to energize the solenoid S5so that uid from the pressure pipe 138 may pass through the valve 209,through a pipe 214, through a throttle valve 215 into the right-hand endchamber of the valve 213 to move the valve 213 toward the left. Duringthis longitudinal shifting movement of the valve 213, fluid may exhaustfrom the motor 130 through the valve 200, through the pipe 212, througha valve chamber 216 in the valve 213 through a pipe 217, a ball checkvalve 218 and a throttle valve 219 and pass through the pipe 220,through they valve 209 into the common exhaust line 188. The speed ofmovement of the valve 213 is regulated by the setting of the throttlevalve 215 so that a predetermined amount of fluid may be metered there-1 through. The rate Vof exhaust of uid from the motor 1 30 is controlledby the setting of the throttle valve 219. A signal light 222 is providedso that the operator may know when the pick or incremental feed is inoperation. A second pick feed cannot be obtained until the first pickfeed has been completed and the timer reset to its initial position. Anelectric light bulb 222 on the upper control unit 162a is connected inseries between the magnetic switches CR8-CR10 and the solenoid S5 andalso connected in series between switches CRS-C117 and the solenoid S6visibly to indicate that the pick feed of the upper slide 87 or thelower slide 82 is operative under control of the timer 221 or the timer281 respectively. A similar set of controls is provided for controllingthe slow and rapid feeding movement of the lower slide S2 A pair ofpushbutton switches PBI and FB2 are provided forcontrolling a pick feedof the lower slide 82 as will bte-hereinafter described.

kThe handv wheel 164 mounted ou a shaft 235 on the lower control unit162 is connected to rotate a cam 242 which is arranged to actuate thecontrol arms 243 and 244 of a pair of limit switches LS3 and LS4respectively when. the hand wheel is rotated either in acounterclockwise or aclockwise direction. The hand wheel 164 is t alsoconnected to rotate a gear 236 which meshes with aslidably 4mounted rackbar 237. The rack bar 237 is connected by a rod 238 to a valve stem 239of the control Avalve 240. A compression spring 241 serves normally tohold the valve stem 239 in a central position. The control valve 240 isprovided with a pair of ports 2.45 and 249 for controlling the slow feedof the lower slide 82. The valve 240 is also provided with a second pairof ports 256 and 257 for controlling the rapid feedingmovement of thelower slide 82. A slidably mounted stop pin, identical with thatillustrated in connection with the hand wheel 163, is provided normallyto limit the rotary motion of the hand wheel 164 so that either theVport 245 or the port 249 is opened to allow iiuid to exhaust through apipe 246, through a throttle valve 247 and-.out-thr'ough the commonexhaust pipe 188. The

